I had what the doctors think was mono in 8th grade (tested positive for it in 9th, so who knows). I got sick (was out of school for a full 2 weeks) and truly never was the same. It totally wiped out my immune system for a few years (things are a bit better now). Diagnosed with Fibro/CF and a whole host of other things by my senior year in HS. It's like whatever it was attacked my brain and took a part of me with it :( Rest up! It's a miserable feeling and there's no point in pushing it!